Chaser for cutting screw-threads.



R. M. PHELAN.

GHASER FOR GUTTING sonsw THREADS.

APPLICATION FILED OUT. 6, 1913.

Patented. July 21, 1914.

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IHI: nmems PETERS CO.PIlL1l'U-LIIHO WASHINGTON. D. C.

P M. PHBLAN.

CHASE-R FOR 001mm SCREW THREADS.

APPLIOATION FILED OGT.6, 1913.

1 1 45% 11 o Patented July 21,1914.

2 SHEETSSHEET 2.

Ema/7% THE NORRIS PETERS cof. FHOTOJJTHOH wAS/l/NCTON, D. c.

snares PAEN RICHARD 1W. PIIELAN, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF T0 ALEXANDER DAVIDSON, OF CHICAGO, ILLINOIS.

CHASER- FOR CUTTING SCREW-THREADS.

Specification of Letters Patent.

Application filed October 8, 1913.

Patented July 21, fillet.

Serial No. 793,637.

1/ 'o (M whom it may concern Be it known that I, RICHARD M. PIIELAN, a citizen of the United States, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Chasers for Cutting Screw-Threads, of which the following is a specification.

The invention relates to tools which are known in the art as chasers; said chasers being used for the cutting of internal and ex ternal threads on metal pipes and other articles, as on bosses, etc.

The object of the invention is to obtain a chaser by means of which either an external or an internal thread may be cut, particularly on what are known as soft metal (as say, brass, copper, and the like), articles, and I have illustrated and described a holder in which said chaser may be conveniently held and easily adjusted for use on a lathe, in the cutting of said threads, so that both the construction and the use of the device may be well understood.

A further object is to obtain a chaser which is so constructed as to lessen the num ber of tools by means of which a given number of different threads on as many different pipes, bosses or other articles, may be out than has heretofore been done; to lessen the cost of making chasers; and to obtain a durable tool or device.

In the drawing accompanying and forming a part of this specification Figure 1 is a top plan view of a chaser embodying this invention. Fig. 2 is a side elevation of the chaser illustrated in Fig. 1. Fig. 3 is an end elevation of said chaser, and a side elevation, indicated by broken lines, of a wheel by means of which the threads may be cut on said chaser. Fig. 4: is an end elevation, viewed on line 4-4 of Fig. 5, in the direction indicated by the arrows. Fig. 5 is a side elevation of said holder, viewed on line 55, of Fig. 4, in the direction indicated by the arrows. Fig. 6 is an elevation of a tool post of a lathe adapted to hold said holder. Fig. 7 is an end elevation of a tube or pipe and the cutting end of the device embodying the invention in suitable relation to cut an external thread on said tube or pipe. And Fig. 8 is a like view of said parts to cut an internal thread.

A. reference character applied to designate a given part is used to indicate said partthroughout the several figures of the draw ing, wherever the same appears.

To those skilled in the art it is known that chasers are used in cutting internal and eX- ternal screw threads on soft metal tubes, pipes and other articles; that is, said metal consists of copper, brass, aluminum and the like; and so far as I am aware the chasers used have consisted of a single cutting point or edge.

A is the part of the chaser which is held in the holder (G) therefor; and is termed by me the body part of said chaser. The ends of body part A are offset, as at B, B and C are screw threads on one of the faces of the offset ends. These screw threads are used to cut corresponding internal, and also external, screw threads, when the chaser is properly adjusted and secured in holder Gr, said holder is secured in post J of a lathe, the article on which the thread is to be cut is in said lathe, and the lathe is turned.

D is a recess on the face of the offset end of the chaser which is provided with the screw threads C. This recess is well illustrated in Fig. by said face being shown in contact with the periphery of the circle which is indicated by broken lines F.

d, (/7 are the edges of the screw threaded ends B, B

E are recesses in the ends of the offset ends B, B recesses E, and also the recesses on the faces of the respective ends B, B are provided to obtain clearing spaces for the chips or cuttings produced in cutting threads with the device.

In cutting an internal thread the edge (Z of a given end is first brought into contact with the work; and in cutting an external thread the edge (Z is first brought into contact with said work.

G is holder which is well adapted to hold the device, and consists of two parts, (g, 9

H is a pin, and 71, h are bosses.

I, 1 are recesses on the meeting faces of parts 9, 9.

J is the tool post of a lathe, and K is an aperture in said post.

L is a set screw by means of which a tool is secured in position in said post.

Holder G fits in aperture K, and is held rigidly in place by set screw L, when said set screw is turned down on said holder. The turning of set screw L on to holder G forces parts g, 9 firmly together, thereby holding this device rigidly in its adjusted position in said holder. The adjustment of this device in said holder is made before set screw L is turned to place.

X is a tube or pipe, (Figs. 7 and 8). In Fig. 7 the cutting edge of the device is properly set to cut an external screw thread on tube or pipe X; and in Fig. 8 said device is positioned to cut an internal screw thread.

This device is operated in a lathe which is provided with means to obtain an advance of the tool post in unison with the pitch of the threads which are to be cut. On a lathe of the above named character this device is adjusted in the tool post, and the article on which the screw thread is to be cut is placed in the lathe. The lathe is then set in motion, (turning toward the operator) and the device advanced to contact with said article. The clearance which is provided by the end recess and the face recess of the device is suilicient to permit the cuttings to clear the work, and no clogging of the device will result. The screw threads on a given end are, therefore, sufficient to cut both an outside and an inside thread; and hence the screw threads on the opposite end of the same device are of a different pitch.

chasers as the same have been heretofore made.

The device is easily removed from holder G and a like device, but with different pitch threads, substituted therefor.

In changing this device from its position to cut an outside thread, (or an inter nal one) to one in which theother kind of a thread may be cut, it is simply turned, (or rotated) in its holder, to a required position. Frequently the tool post does not require to be changed.

The device, constructed as described, and used as stated, will cuta thread close to a shoulder.

I claim A chaser consisting of a body part provided with an oflset at the end thereof, the face of said offset end provided with a recess and wlth screw threads, and the end oisaid offset recessed.

RICHARD M. PHELAN.

In the presence of- ALEXANDER DAVIDSON, CHARLES TURNER BROWN.

Copies of thls patent may be obtained for five cents each, by addressing the Commissioner of Patents,

, Washington, D. 0. 

